3.5 KiB
3.5 KiB
ShowAsInputPin
- 功能描述： 使得UMaterialExpression里的一些基础类型属性变成材质节点上的引脚。
- 使用位置： UPROPERTY
- 引擎模块： Material
- 元数据类型： bool
- 限制类型： UMaterialExpression里的属性
- 常用程度： ★★★
使得UMaterialExpression里的一些基础类型属性变成材质节点上的引脚。
- 所谓基础类型，指的是float，FVector这种常用的类型。
- 默认这些基础类型属性是不显示为引脚的。
- ShowAsInputPin 值有两个选项，Primary可以直接显示出来，Advanced需要展开箭头后显示。
测试代码：
public:
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = PinTest)
float MyFloat;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = PinTest, meta = (ShowAsInputPin = "Primary"))
float MyFloat_Primary;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = PinTest, meta = (ShowAsInputPin = "Advanced"))
float MyFloat_Advanced;
测试结果：
可见MyFloat没有显示在节点上。
MyFloat_Primary显示在节点上。
MyFloat_Advanced需要展开箭头后才显示出来。
原理：
遍历UMaterialExpression里的属性，根据含有ShowAsInputPin 的类型来生成引脚。
TArray<FProperty*> UMaterialExpression::GetPropertyInputs() const
{
TArray<FProperty*> PropertyInputs;
static FName OverridingInputPropertyMetaData(TEXT("OverridingInputProperty"));
static FName ShowAsInputPinMetaData(TEXT("ShowAsInputPin"));
for (TFieldIterator<FProperty> InputIt(GetClass(), EFieldIteratorFlags::IncludeSuper, EFieldIteratorFlags::ExcludeDeprecated); InputIt; ++InputIt)
{
bool bCreateInput = false;
FProperty* Property = *InputIt;
// Don't create an expression input if the property is already associated with one explicitly declared
bool bOverridingInputProperty = Property->HasMetaData(OverridingInputPropertyMetaData);
// It needs to have the 'EditAnywhere' specifier
const bool bEditAnywhere = Property->HasAnyPropertyFlags(CPF_Edit);
// It needs to be marked with a valid pin category meta data
const FString ShowAsInputPin = Property->GetMetaData(ShowAsInputPinMetaData);
const bool bShowAsInputPin = ShowAsInputPin == TEXT("Primary") || ShowAsInputPin == TEXT("Advanced");
if (!bOverridingInputProperty && bEditAnywhere && bShowAsInputPin)
{
// Check if the property type fits within the allowed widget types
FFieldClass* PropertyClass = Property->GetClass();
if (PropertyClass == FFloatProperty::StaticClass()
|| PropertyClass == FDoubleProperty::StaticClass()
|| PropertyClass == FIntProperty::StaticClass()
|| PropertyClass == FUInt32Property::StaticClass()
|| PropertyClass == FByteProperty::StaticClass()
|| PropertyClass == FBoolProperty::StaticClass()
)
{
bCreateInput = true;
}
else if (PropertyClass == FStructProperty::StaticClass())
{
FStructProperty* StructProperty = CastField<FStructProperty>(Property);
UScriptStruct* Struct = StructProperty->Struct;
if (Struct == TBaseStructure<FLinearColor>::Get()
|| Struct == TBaseStructure<FVector4>::Get()
|| Struct == TVariantStructure<FVector4d>::Get()
|| Struct == TBaseStructure<FVector>::Get()
|| Struct == TVariantStructure<FVector3f>::Get()
|| Struct == TBaseStructure<FVector2D>::Get()
)
{
bCreateInput = true;
}
}
}
if (bCreateInput)
{
PropertyInputs.Add(Property);
}
}
return PropertyInputs;
}